I have had this document for a long time. I admit that I’ve mostly ignored it but found it very interesting reading. One thing I’ve tried:
Using just the weight of the blade, very very lighlty pull the razor about one or two millimeters in a direction parallel to the razor’s edge [i.e. instead of edge leading or spine leading, move the razor slightly back and forth perpendicular to the stone.–JDR]. Don’t move any further than that.
There’s a video of Japanese sharpener who, I think, worked with Iwasaki doing this technique. I tried it; testing sharpness and doing microscope images before and after. I found that the edge cleaned up a little bit and became slightly keener. But I was at it for 10 minutes - well into the level of diminishing returns IMO. I made a video of this. Go to the 1hr mark (the video is far too long) and proceed from there.
I’ve had it a while too, just occurred to me it fits well here. I definitely don’t do that for 10 minutes but often a few times here and there almost out of superstition where I hope it might clean up a minor foil edge in case I’d used too much pressure. Thanks for the vid, I’d never attempted to ascertain if this was actually doing anything so your experiment is encouraging. Before this document I saw it mentioned in the balsa strop thread at B&B as a “pull stroke”.
I assume that Iwasaki primarily used a sequence of nagura on a very hard finishing stone. In that system, any edge conditions you have at the finishing stages are difficult to deal with because the abrasive on the stone surface and in a finishing nagura is so small that only a tiny amount of material is removed with each stroke. So, it will take a lot of strokes to clean edge anomalies under those conditions. There are other ways to accomplish burr removal and wire-edge removal. Iwaski’s method seemed valid to me. As I mentioned before, it is not what I do normally.
